Pollen Percentage and Influx Analyses in South-East Ireland: A Contribution to the Ecological History of the Late-Glacial Period

1978 ◽  
Vol 66 (1) ◽  
pp. 297 ◽  
Author(s):  
Alan J. Craig
Keyword(s):  
Late Glacial ◽  
Glacial Period ◽  
Ecological History ◽  
Late Glacial Period ◽  
History Of

Late-glacial deposits at Llyn Dwythwch and Nant Ffrancon, Caernarvonshire

1962 ◽  
Vol 244 (716) ◽  
pp. 459-481 ◽  
Keyword(s):  
Vegetation History ◽  
Late Glacial ◽  
Glacial Period ◽  
Late Glacial Period ◽  
Lacustrine Deposits ◽  
Kettle Hole ◽  
Lycopodium Annotinum ◽  
Northern Distribution ◽  
History Of ◽  
Zone Ii

The stratigraphy of sediments in two lake basins in the Caernarvonshire mountains at 600 and 900 ft. O.D. is described and it is shown that the basal layers were deposited in the Late-glacial Period. The deposits of a third site occupying a kettle-hole in morainic gravels at 1223 ft. O.D. are described and here the Late-glacial Period is not represented. The relation of these sites to the youngest corrie moraines of the district indicates that the latter were formed during the post-Allerod climatic regression (Zone III). The vegetation history of the district was studied by means of pollen analysis of lacustrine deposits from the two first-mentioned sites (above). The vegetation of the Late-glacial Period at first formed tundra (Zone I) in which arctic-alpines, notably Betula , flourished together with species of oceanic and oceanic-northern distribution and calcicolous, eutrophic and moderately thermophilous plants. The spread of juniper scrub preceded the arrival of tree birches, which form ‘park-tundra’ in Zone II at Nant Ffrancon but failed to grow as high as Llyn Dwythwch. The birch ‘ parktundra’ is considered to have covered Britain south of the Forth-Clyde at low altitudes and to have occupied central and eastern Ireland at this time. The climatic deterioration of Zone III is clearly registered by the decline of juniper and tree birch and the local severity of conditions is demonstrated by the increased abundance of the chianophilous fern, Cryptogramma crispa, Lycopodium selago, Saussurea alpina and other montane herbs. The extensive occurrence of solifluxion, augmented by glacier streams, brought down silt and clay into the lakes. The ensuing amelioration in climate and the course of forest development through the Post-glacial Period is briefly traced and the persistence of certain elements of the present mountain flora from the Late-glacial Period demonstrated. A description is given of the spores of Cryptogramma crispa which together with Lycopodium annotinum and Saussurea alpina are new to British Late-glacial records.

XIX.—The Late-glacial History of the Highlands and Islands of Scotland

1955 ◽  
Vol 62 (3) ◽  
pp. 769-928 ◽  
Author(s):  
J. K. Charlesworth
Keyword(s):  
Late Glacial ◽  
Glacial Period ◽  
Glacial History ◽  
The West ◽  
Orkney Islands ◽  
Second Stage ◽  
Late Glacial Period ◽  
The North ◽  
Moray Firth ◽  
History Of

SynopsisFrom the abounding moraines, drainage features (fig. 21) and other marginal indications an attempt has been made to reconstruct the successive phases of the ice in its retreat into the corries of the Highlands and Islands (Pl. I). Two late-glacial stages are recognised. During the first, the Highland Glaciation, an ice-margin ran from the Orkney Islands across the mouth of the Moray Firth to the Buchan and out to sea north of Aberdeen. Twelve substages (A–L) of retreat, arbitrarily selected, have been traced through the country, except in the Moraineless West where they are unrepresented.At the maximum of the second stage, the Moraine Glaciation, the ice readvanced to the line stage M (beaded line in Pl. I). The retreat from this line, the inner boundary of the Moraineless West and of the 100-foot raised beach (Pl. I), is divided into nine substages (N–V), based upon a consideration of snowlines. Substage N corresponds to the 50-foot raised beach, substage P to an important readvance.The snowline throughout the late-glacial period ran in the west parallel with the meridians and rose eastwards. The disposition of the snowlines for stage M is given in fig. 22, p. 900.The distribution of the ice in the British Isles during the North British, Highland and Moraine Glaciations is represented in fig. 23, p. 923.

Holocene vegetation history in Romanian Subcarpathians

2009 ◽  
Vol 72 (2) ◽  
pp. 164-173 ◽  
Author(s):  
Ioan Tantau ◽  
Maurice Reille ◽  
Jacques-Louis de Beaulieu ◽  
Sorina Farcas ◽  
Simon Brewer
Keyword(s):  
Pollen Analysis ◽  
Vegetation History ◽  
Late Glacial ◽  
Fast Response ◽  
Rapid Expansion ◽  
Glacial Period ◽  
Climatic Warming ◽  
Peat Core ◽  
Late Glacial Period ◽  
History Of

AbstractPollen analysis from a peat core 7.0 m in length, taken from a bog near Bisoca, in a mid-altitude area of the Buzăului Subcarpathian mountains, is used to reconstruct the postglacial vegetation history of the region. The vegetation record, which is supported by twelve 14C dates, starts at the end of the Late Glacial period. At the Late Glacial/Holocene transition, open vegetation was replaced by forest, suggesting a fast response to climatic warming. The Holocene began with the expansion of Betula, Pinus and Ulmus, followed, after 11,000 cal yr BP, by Fraxinus, Quercus, Tilia and Picea. The rapid expansion of these taxa may be due to their existence in the area during the Late Glacial period. At ca. 9200 cal yr BP, Corylus expanded, reaching a maximum after 7600 cal yr BP. The establishment of Carpinus occurred at ca. 7200 cal yr BP, with a maximum at ca. 5700 cal yr BP. Fagus pollen is regularly recorded after 7800 cal yr BP and became dominant at ca. 2000 cal yr BP. The first indications of human activities appear around 3800 cal yr BP.

scholarly journals History of Vegetation of Ulyanovsk City and Its Surroundings

2020 ◽  
pp. 3-14
Author(s):  
N. V. Blagoveshenskaya ◽  
Ch. T. Zamaldinova ◽  
G. V. Funk
Keyword(s):  
Late Glacial ◽  
Pine Forests ◽  
Forest Steppe ◽  
Secondary Forests ◽  
Glacial Period ◽  
Residential Areas ◽  
Late Glacial Period ◽  
History Of Vegetation ◽  
History Of ◽  
Grass Meadow

The vegetation evolution on the modern territory of the Ulyanovsk City and its surroundings, beginning from the late glacial period, can be presented as follows. 11,000– 10,300 years ago: a “tundra-steppe” with wormwood-mazy, horsetail, fern, shrubbygreen-green communities. 10,300–9,500 years ago: wormwood-haze-cenotic cenoses, isolated islets of sparse pine forests. 9,500–8,500 years ago: sagebrush-cerebral, cereal steppes and pine forests. 8,500–8,000 years ago: turf-grass, grass-meadow-grass meadow steppes and pine forests. 8,000–6,000 years ago: forbred-cereal, less often turfgrass meadow steppes, birch, and birch-pine forests, the appearance of deciduous species. 6,000–4,500 years ago: pine-broad-leaved, broad-leaved forests, mixed-grassgrass meadow steppes, and the maximum afforestation. 4,500–3,200 years ago: broadleaved, pine-broadleaf forests, and the appearance of agrocenoses. 3200–2500 years ago: pine, pine-birch forests, reduction of broad-leaved species, the expansion of turfgrass steppes and agrocenoses. 2,500–700 years ago: the emergence of secondary forests and meadow steppes (fescue, wormwood-cereal), the expansion of agrocenoses. 700–350 years ago: pine, pine-birch, pine-broadleaf forests, reduction of agrocenoses. 350 years ago till the present time: a sharp decline in forests, the predomination of secondary pine, broad-leaved, small-leaved, mixed forests and secondary meadow steppes, the expansion of agrocenoses and residential areas. Thus, the vegetation of the territory of the Ulyanovsk City and its environs since the late glacial period varied from the steppe one (11,000–8,000 years ago) to the forest-steppe one (8,000–700 years ago) and again to the steppe one (700 years ago – modern time). The least afforestation of the territory was observed from 11,000 to 9,500 years ago (3–4%) and from 350 years ago to the present (6–7%). The greatest afforestation of the forest-steppe was from 6,000 to 3,200 years ago, when the forest-to-steppe ratio was equal.

Late-glacial and Post-glacial history of the Chalk escarpment near Brook, Kent

1964 ◽  
Vol 248 (745) ◽  
pp. 135-204 ◽  
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Valley Floor ◽  
Glacial Period ◽  
Late Neolithic ◽  
Local Conditions ◽  
Arable Farming ◽  
History Of

This paper describes the morphology of a small piece of the Chalk escarpment near Brook in east Kent, and reconstructs its history since the end of the Last Glaciation. The escarpment contains a number of steep-sided valleys, or coombes, with which are associated deposits of chalk debris, filling their bottoms and extending as fans over the Gault Clay plain beyond. Here the fans overlie radiocarbon-dated marsh deposits of zone II (10 000 to 8800 B.C.) of the Late-glacial Period. The debris fans were formed and the coombes were cut very largely during the succeeding zone III (8800 to 8300 B.C.). The fans are the products of frost-shattering, probably transported by a combination of niveo-fluvial action and the release of spring waters; intercalated seams of loess also occur. The molluscs and plants preserved in the Late-glacial deposits give a fairly detailed picture of local conditions. The later history of one of the coombes, the Devil’s Kneadingtrough, is reconstructed. The springs have effected virtually no erosion and have probably always emerged more or less in their present position. In the floor of the coombe the periglacial chalk rubbles of zone III are covered by Postglacial deposits, mainly hillwashes. They are oxidized and yield no pollen, but contain rich faunas of land Mollusca, which are presented in the form of histograms revealing changing local ecological and climatic conditions. During most of the Post-glacial Period, from the end of zone III until about the beginning of zone VIII, very little accumulation took place on the coombe floor. But below the springs there are marsh deposits which span much of this interval. They yield faunas of considerable zoogeographical interest. The approximate beginning of zone VII a (Atlantic Period) is reflected by a calcareous tufa, which overlies a weathering horizon, and represents an increase in spring flow. Two clearance phases are deduced from the molluscan record. The first may have taken place at least as early as the Beaker Period (Late Neolithic/earliest Bronze Age); the second is probably of Iron Age ‘A’ date. In Iron Age times the subsoil was mobilized and a phase of rapid hillwashing began. As a result the valley floor became buried by humic chalk muds. The prime cause of this process was probably the beginning of intensive arable farming on the slopes above the coombe; a possible subsidiary factor may have been the Sub-Atlantic worsening of climate. The muds yield pottery ranging in date from Iron Age ‘Kentish first A’ ( ca . 500 to ca . 300 B.C.) to Romano-British ware of the first or second centuries A.D. Evidence is put forward for a possible climatic oscillation from dry to wet taking place at about the time of Christ. In the later stages of cultivation, possibly in the Roman Era, the valley floor was ploughed and given its present-day form.

Progressive glacial retreat in the Southern Altiplano (Uturuncu volcano, 22°S) between 65 and 14 ka constrained by cosmogenic 3He dating

2014 ◽  
Vol 82 (1) ◽  
pp. 209-221 ◽  
Author(s):  
Pierre-Henri Blard ◽  
Jérôme Lave ◽  
Kenneth A. Farley ◽  
Victor Ramirez ◽  
Nestor Jimenez ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Late Glacial ◽  
Glacial Period ◽  
Tropical Andes ◽  
Equilibrium Line Altitude ◽  
Glacial Retreat ◽  
Late Glacial Period ◽  
Cold Episode ◽  
Glacial Landforms ◽  
Exposure Ages

AbstractThis work presents the first reconstruction of late Pleistocene glacier fluctuations on Uturuncu volcano, in the Southern Tropical Andes. Cosmogenic 3He dating of glacial landforms provides constraints on ancient glacier position between 65 and 14 ka. Despite important scatter in the exposure ages on the oldest moraines, probably resulting from pre-exposure, these 3He data constrain the timing of the moraine deposits and subsequent glacier recessions: the Uturuncu glacier may have reached its maximum extent much before the global LGM, maybe as early as 65 ka, with an equilibrium line altitude (ELA) at 5280 m. Then, the glacier remained close to its maximum position, with a main stillstand identified around 40 ka, and another one between 35 and 17 ka, followed by a limited recession at 17 ka. Then, another glacial stillstand is identified upstream during the late glacial period, probably between 16 and 14 ka, with an ELA standing at 5350 m. This stillstand is synchronous with the paleolake Tauca highstand. This result indicates that this regionally wet and cold episode, during the Heinrich 1 event, also impacted the Southern Altiplano. The ELA rose above 5450 m after 14 ka, synchronously with the Bolling–Allerod.

scholarly journals Surface profiles and basal shear stresses of outlet glaciers from a Late-glacial mountain ice field in western Scotland

1991 ◽  
Vol 37 (125) ◽  
pp. 77-88 ◽  
Author(s):  
Peter W. Thorp
Keyword(s):  
Late Glacial ◽  
Shear Stresses ◽  
Glacial Period ◽  
Late Glacial Period ◽  
Bedrock Topography ◽  
Pore Water Pressures ◽  
Basal Sliding ◽  
Ice Field ◽  
Surface Profiles ◽  
Basal Shear

Abstract Surface and basal long profiles are reconstructed for 13 outlet glaciers that drained ice from a large ice field (80 km by 120 km) that formed in the western Grampians of Scotland during part of the Late-glacial period (c, 14000–10000years BP). Basal shear stresses are calculated at 5 km intervals along the central flowlines of the reconstructed outlet glaciers. Individual basal shear stresses for the outlet glaciers range from 10 to 204 kPa. Variations in calculated basal shear stresses within and between the glaciers are mainly explained by differences in bedrock topography, extending and compressional flow, and by differences in basal boundary conditions. Low basal shear stresses (<53kPa) calculated for the terminal zones of Creran, Menteith and Lomond glaciers are partly explained by the overriding of glaciomarine clays with inferred high pore-water pressures and a low yield strength that may have led to rapid basal sliding and thinning of the ice lobes.

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